1. Field of the Invention
The present invention relates to an optical system used as an interchangeable lens for a single-lens reflex camera and a photocopy lens, an optical apparatus using the optical system.
2. Related Background Art
There have been proposed a lot of cases that a so-called Double-Gauss type lens system is used as a lens system for a single-lens reflex camera or a photocopy lens system such as Japanese Examined Patent Application Publication No. 58-057725.
However, in the optical system disclosed in Japanese Examined Patent Application Publication No. 58-057725, spherical aberration, curvature of field, and distortion have been excellently corrected, but sagittal coma, which is specially generated in a Double-Gauss type lens system upon fully opening the aperture stop, considerably remains, so that it has been hardly to say that the optical system has sufficiently high optical performance.